A130685 a(0)=0; a(n) = n-th integer from among those positive integers which are coprime to (a(n-1) + n).

0, 1, 2, 3, 4, 7, 6, 7, 14, 9, 10, 19, 12, 16, 49, 29, 29, 35, 18, 19, 32, 21, 22, 43, 24, 29, 36, 46, 57, 59, 30, 31, 55, 71, 73, 103, 36, 37, 71, 107, 68, 41, 42, 57, 44, 45, 58, 103, 48, 49, 82, 62, 163, 157, 54, 55, 86, 68, 199, 179, 60

Offset

0,3

Links

Table of n, a(n) for n=0..60.

Example

a(13) + 14 = 30. The positive integrs which are coprime to 30 are 1, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, ...; the 14th of these integers is 49, so a(14) = 49.

Maple

a[0]:=0: for n to 60 do CP:={}: for j while nops(CP)<=n do if gcd(n+a[n-1], j) =1 then CP:=`union`(CP, {j}) else end if end do: a[n]:=CP[n] end do: seq(a[n], n=0..60); # Emeric Deutsch, Aug 28 2007

Crossrefs

Sequence in context: A074846 A120225 A247798 * A210202 A358201 A358176

Adjacent sequences: A130682 A130683 A130684 * A130686 A130687 A130688

Keyword

nonn

Author

Leroy Quet, Aug 12 2007

Extensions

More terms from Emeric Deutsch, Aug 28 2007

Status

approved